<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>6.3 CSS3 新的字体单位rem-大结局</title>
    <style>
        html{
            font-size: 62.5%;
        }
        body{
            font-size: 1.4rem;
        }
        h1{
            font-size: 2.4rem;
        }
    </style>
</head>
<body>
 <div>hello panda!</div>
 <h1>hello panda!</h1>
</body>
</html>